scholarly journals Solid-State Welding of the Nanostructured Ferritic Alloy 14YWT Using a Capacitive Discharge Resistance Welding Technique

Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 23
Author(s):  
Calvin Robert Lear ◽  
Jonathan Gregory Gigax ◽  
Matthew M. Schneider ◽  
Todd Edward Steckley ◽  
Thomas J. Lienert ◽  
...  
Keyword(s):  
Solid State ◽  
Weld Line ◽  
Base Material ◽  
Fusion Welding ◽  
Resistance Welding ◽  
Ferritic Alloy ◽  
Capacitive Discharge ◽  
Nano Oxide ◽  
End Caps ◽  
Temperature Strain

Joining nanostructured ferritic alloys (NFAs) has proved challenging, as the nano-oxides that provide superior strength, creep resistance, and radiation tolerance at high temperatures tend to agglomerate, redistribute, and coarsen during conventional fusion welding. In this study, capacitive discharge resistance welding (CDRW)—a solid-state variant of resistance welding—was used to join end caps and thin-walled cladding tubes of the NFA 14YWT. The resulting solid-state joints were found to be hermetically sealed and were characterized across the weld region using electron microscopy (macroscopic, microscopic, and nanometer scales) and nanoindentation. Microstructural evolution near the weld line was limited to narrow (~50–200 μm) thermo-mechanically affected zones (TMAZs) and to a reduction in pre-existing component textures. Dispersoid populations (i.e., nano-oxides and larger oxide particles) appeared unchanged by all but the highest energy and power CDRW condition, with this extreme producing only minor nano-oxide coarsening (~2 nm → ~5 nm Ø). Despite a minimal microstructural change, the TMAZs were found to be ~10% softer than the surrounding base material. These findings are considered in terms of past solid-state welding (SSW) efforts—cladding applications and NFA-like materials in particular—and in terms of strengthening mechanisms in NFAs and the potential impacts of localized temperature–strain conditions during SSW.

scholarly journals Electron beam welding of rectangular copper wires applied in electrical drives

2021 ◽  
Author(s):  
Tamás Tóth ◽  
Jonas Hensel ◽  
Sven Thiemer ◽  
Philipp Sieber ◽  
Klaus Dilger
Keyword(s):  
Electron Beam ◽  
Oxygen Content ◽  
Electron Beam Welding ◽  
Base Material ◽  
Fusion Welding ◽  
Eb Welding ◽  
Technological Parameters ◽  
Low Level ◽  
Residual Oxygen ◽  
Ofe Copper

AbstractThe so-called hairpin winding technology, which is specially tailored to electrical traction components, deploys rectangular plug-in copper wires in the stator. The fusion welding of the adjacent wire ends is associated with challenges due to the high thermal conductivity as well as the porosity formation of the copper. During this study, the electron beam (EB) welding of electrolytic tough pitch (ETP) and oxygen-free electronic grade (OFE) copper connectors was investigated. Subsequently, the specimens underwent X-ray computed tomography (CT) and metallographic examinations to characterize the joints. It was discovered that the residual oxygen content of the base material is responsible for the pore formation. With only a very low level of oxygen content in the copper, a porosity- and spatter-free welding can be reproducibly realized using the robust EB welding technology, especially for copper materials. By optimizing the parameters accordingly, joints exhibiting a low level of porosity were achieved even in the case of the alloy containing a high amount of residual oxygen. Beyond this, detailed analyses in terms of pore distribution were carried out and a good correlation between technological parameters and welding results was determined.

scholarly journals PRELIMINARY STUDY ON EFFECT OF ROD GEOMETRY IN FHPP BETWEEN FE55006 NODULAR CAST IRON AND SAE 8620 STELL

2019 ◽  
Vol 16 (31) ◽  
pp. 642-650
Author(s):  
Douglas MARTINAZZI ◽  
Guilherme V. B LEMOS ◽  
Renan M LANDELL ◽  
Diogo T BUZZATTI ◽  
André BRUSIUS ◽  
...  
Keyword(s):  
Cast Iron ◽  
Base Material ◽  
Nodular Cast Iron ◽  
Lower Surface ◽  
Fusion Welding ◽  
Plastic State ◽  
Cast Irons ◽  
Preliminary Study ◽  
Sae 8620 Steel ◽  
Made In

Nodular cast irons are an excellent alternative in manufacturing process of axels due to their characteristics and good mechanical properties. However, the necessity of joining the axels to the gears and other components, made in carbon steel, is a great challenge. Traditional fusion welding methods applied to dissimilar ferrous materials are not deeply studied. In this context, it is well known that different materials have distinct melting points which can cause difficulty in welding, besides of defects formation from solidification. Therefore, modern joining processes such as Friction Hydro Pillar Processing (FHPP) are a great alternative. In this technology, a consumable rod is rotated against to a base material, generating the heat due to the friction, promoting materials in the plastic state and then producing the weld. Hence, this work presents a preliminary study of FHPP between the FE55006 nodular cast iron and SAE 8620 steel and evaluates the rod geometry influence on microstructure and surface stresses of the welded joints. Two rod geometries were used and two welds were further produced. The results indicated that an increase in the rod contact area promoted a lower surface stress as well as a better welded joint.

Effects of Aging on the Mechanical Properties of Pipeline Steels

2008 ◽  
Author(s):  
Martin Hukle ◽  
Brian Newbury ◽  
Dan Lillig ◽  
Jonathan Regina ◽  
Agnes Marie Horn
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Uniform Elongation ◽  
Weld Line ◽  
Base Material ◽  
Pipeline System ◽  
Line Pipe ◽  
Pipeline Steels ◽  
Reduction Of Area ◽  
Effects Of Aging

The intelligent design of a given pipeline system intended for operation beyond the elastic limit should incorporate specific features into both the base material (line pipe) and girth weld that enable the affected system to deform safely into the plastic regime within the intended strain demand limits. The current paper focuses on the mechanical properties known to influence the strain capacity of the base material (i.e., line pipe steel independent of the girth weld). Line pipe mechanical properties of interest include: longitudinal yield strength, tensile strength, yield to tensile strength ratio, reduction of area, elongation and uniform elongation. Of particular interest (in consideration of the conventional thermally applied corrosion protection coating systems to be employed), are the longitudinal mechanical properties in the “aged” condition. The present study investigates six (6) different pipeline steels encompassing grades X60 (415 MPa) to X100 (690 MPa), and includes both UOE Submerged Arc Welded - Longitudinal (SAW-L) and seamless (SMLS) forming methods.

Microstructures and Mechanical Properties of Solid-State Welded Steels

2021 ◽  
Vol 21 (9) ◽  
pp. 4877-4880
Author(s):  
Gyeong Woo Kim ◽  
Se Min Jeong
Keyword(s):  
Mechanical Properties ◽  
Solid State ◽  
Grain Refinement ◽  
Friction Welding ◽  
Vickers Microhardness ◽  
Rotation Speed ◽  
Base Material ◽  
Tensile Specimen ◽  
Refined Grains ◽  
Microstructures And Mechanical Properties

This study aimed to evaluate the soundness of solid-state welded steels. STS 430F alloy with a rod type was selected as experimental material, and the friction welding was conducted at a rotation speed of 2,000 RPM and upset length of 3 mm. The application of friction welding on STS 430F rods led to significant grain refinement in the welded zone (1.3 µm) compared to that observed in the base material (16.8 µm). The refined grains in the welds contributed to the development of the mechanical properties. In particular, the Vickers microhardness was increased by approximately 25% compared to the base material, and the fracture at the tensile specimen of the welds occurred at the base material zone and not in the welded zone, which suggests a soundly welded state on the STS 430F rods.

scholarly journals Additive Friction Stir-Enabled Solid-State Additive Manufacturing for the Repair of 7075 Aluminum Alloy

2019 ◽  
Vol 9 (17) ◽  
pp. 3486 ◽  
Author(s):  
R. Joey Griffiths ◽  
Dylan T. Petersen ◽  
David Garcia ◽  
Hang Z. Yu
Keyword(s):  
Aluminum Alloy ◽  
Additive Manufacturing ◽  
Solid State ◽  
Side Wall ◽  
Fusion Welding ◽  
7075 Aluminum Alloy ◽  
Hole Filling ◽  
Friction Stir ◽  
Advantages And Disadvantages ◽  
Through Hole

The repair of high strength, high performance 7075 aluminum alloy is essential for a broad range of aerospace and defense applications. However, it is challenging to implement it using traditional fusion welding-based approaches, owing to hot cracking and void formation during solidification. Here, the use of an emerging solid-state additive manufacturing technology, additive friction stir deposition, is explored for the repair of volume damages such as through -holes and grooves in 7075 aluminum alloy. Three repair experiments have been conducted: double through-hole filling, single through-hole filling, and long, wide-groove filling. In all experiments, additive friction stir deposition proves to be effective at filling the entire volume. Additionally, sufficient mixing between the deposited material and the side wall of the feature is always observed in the upper portions of the repair. Poor mixing and inadequate repair quality have been observed in deeper portions of the filling in some scenarios. Based on these observations, the advantages and disadvantages of using additive friction stir deposition for repairing volume damages are discussed. High quality and highly flexible repairs are expected with systematic optimization work on process control and repair strategy development in the future.

scholarly journals A Study on Rotary Friction Welding of Titanium Alloy (Ti6Al4V)

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Ho Thi My Nu ◽  
Truyen The Le ◽  
Luu Phuong Minh ◽  
Nguyen Huu Loc
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloys ◽  
Friction Welding ◽  
Base Material ◽  
Welding Process ◽  
High Strength ◽  
Fusion Welding ◽  
Experimental Results ◽  
Thermomechanical Model ◽  
Rotary Friction Welding

The selection of high-strength titanium alloys has an important role in increasing the performance of aerospace structures. Fabricated structures have a specific role in reducing the cost of these structures. However, conventional fusion welding of high-strength titanium alloys is generally conducive to poor mechanical properties. Friction welding is a potential method for intensifying the mechanical properties of suitable geometry components. In this paper, the rotary friction welding (RFW) method is used to study the feasibility of producing similar metal joints of high-strength titanium alloys. To predict the upset and temperature and identify the safe and suitable range of parameters, a thermomechanical model was developed. The upset predicted by the finite element simulations was compared with the upset obtained by the experimental results. The numerical results are consistent with the experimental results. Particularly, high upset rates due to generated power density and forging pressure overload that occurred during the welding process were investigated. The performances of the welded joints are evaluated by conducting microstructure studies and Vickers hardness at the joints. The titanium rotary friction welds achieve a higher tensile strength than the base material.

Remote Resistance Welding of Zr-4 Endplate for DUPIC Fuel Fabrication

2008 ◽  
Vol 580-582 ◽  
pp. 397-400 ◽  
Author(s):  
Soo Sung Kim ◽  
Dae Seo Koo ◽  
Geun Il Park ◽  
Jin Hyun Koh
Keyword(s):  
Preliminary Investigation ◽  
Welding Process ◽  
Resistance Welding ◽  
Optimum Conditions ◽  
Candu Reactors ◽  
Welding Technology ◽  
Fuel Fabrication ◽  
Hands On ◽  
End Caps ◽  
Direct Use

The remote resistance welding technology in the hot cell environment for DUPIC (Direct Use of spent PWR fuel In CANDU reactors) fuel fabrication was established. To do this, a preliminary investigation for hands-on fuel fabrication outside the hot cell was conducted in the consideration of constraints caused by welding in the hot cell. Further welding experiments were carried out to improve the RW process. A remote resistance welding apparatus was developed. The characteristics of welds made by RW and LBW were compared in terms of the weld nugget penetrations and torque strength. It was found that resistance welding was a more suitable welding process for joining the endplate to the end caps in the hot cell. The optimum conditions for RW in the hot cell operation in a remote manner were also obtained.

scholarly journals Analysis of the Oscillation Behavior of Hybrid Aluminum/Steel Joints Realized by Ultrasound Enhanced Friction Stir Welding

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1079
Author(s):  
Marco Thomä ◽  
Andreas Gester ◽  
Guntram Wagner ◽  
Marco Fritzsche
Keyword(s):  
Friction Stir Welding ◽  
Base Material ◽  
Fusion Welding ◽  
Laser Vibrometer ◽  
Particle Volume ◽  
Dissimilar Joints ◽  
Additional Energy ◽  
Power Ultrasound ◽  
Friction Stir ◽  
Ultrasound Enhancement

Friction stir welding (FSW) is an innovative solid-state joining process, which is suitable for joining dissimilar materials with strongly differing physical and chemical properties such as aluminum and steel. Where other joining methods such as fusion welding struggle to achieve appropriate joint strengths due to the excessive formation of brittle aluminum-rich intermetallic phases (IMP), FSW joints of aluminum and steel only show small layers of IMP, thus, sufficient tensile strengths in proximity to the maximum tensile strength of the weaker aluminum base material can be reached. With the aim to optimize the mechanical and microstructural properties of such dissimilar joints for widening the field for possible industrial applications, several hybrid friction stir welding methods have been developed which include an additional energy input, whereas the ultrasound enhancement (USE-FSW) is one of the most promising. The current work was carried out on AA6061/DC04 joints which were successfully friction stir welded with and without ultrasound support, in respect to the influence of varying the ultrasound transmission side. The functionality of the USE-FSW setup could be verified by multi point laser vibrometer measurements. Additionally, a higher proportion of transversal oscillation for the transmission of power ultrasound into aluminum could be detected using a scanning vibrometer. In comparison to the conventionally friction stir welded joints the ultrasound enhancement led to an avoidance of weld defects and an increase of the steel particle volume in the stir zone. The joint produced with power ultrasound transmission via aluminum resulted in a more uniform interface.

Phenomenological Modeling of Fusion Welding Processes

MRS Bulletin ◽  
1994 ◽  
Vol 19 (1) ◽  
pp. 29-35 ◽  
Author(s):  
S.A. David ◽  
T. DebRoy ◽  
J.M. Vitek
Keyword(s):  
Solid State ◽  
Heat Source ◽  
Base Metal ◽  
Weld Pool ◽  
Welding Process ◽  
Poor Performance ◽  
Consumer Products ◽  
Phase Changes ◽  
Fusion Welding ◽  
Welding Processes

Welding is utilized in 50% of the industrial, commercial, and consumer products that make up the U.S. gross national product. In the construction of buildings, bridges, ships, and submarines, and in the aerospace, automotive, and electronic industries, welding is an essential activity. In the last few decades, welding has evolved from an empirical art to a more scientifically based activity requiring synthesis of knowledge from various disciplines. Defects in welds, or poor performance of welds, can lead to catastrophic failures with costly consequences, including loss of property and life.Figure 1 is a schematic diagram of the welding process showing the interaction between the heat source and the base metal. During the interaction of the heat source with the material, several critical events occur: melting, vaporization, solidification, and solid-state transformations. The weldment is divided into three distinct regions: the fusion zone (FZ), which undergoes melting and solidification; the heat-affected zone (HAZ) adjacent to the FZ, that may experience solid-state phase changes but no melting; and the unaffected base metal (BM).Creating the extensive experimental data base required to adequately characterize the highly complex fusion welding process is expensive and time consuming, if not impractical. One recourse is to simulate welding processes either mathematically or physically in order to develop a phenomenological understanding of the process. In mathematical modeling, a set of algebraic or differential equations are solved to obtain detailed insight of the process. In physical modeling, understanding of a component of the welding process is achieved through experiments designed to avoid complexities that are unrelated to the component investigated.In recent years, process modeling has grown to be a powerful tool for understanding the welding process. Using computational modeling, significant progress has been made in evaluating how the physical processes in the weld pool influence the development of the weld pool and the macrostructures and microstructures of the weld.

Assessment of Powder Metallurgy-Hot Isostatic Pressed Nozzle-to-Safe End Transition Joints

2017 ◽  
Author(s):  
Ben Sutton ◽  
David Gandy
Keyword(s):  
Heat Treatment ◽  
Powder Metallurgy ◽  
Alloy Steel ◽  
Material Selection ◽  
Base Material ◽  
Impact Testing ◽  
Fusion Welding ◽  
Diffusion Region ◽  
Low Alloy Steel ◽  
Dissimilar Metal

Dissimilar metal nozzle-to-safe end welds represent a complex manufacturing operation for nuclear reactor fabrication. Transitioning from a low alloy steel nozzle to corrosion-resistant reactor coolant system piping systems requires weld buttering, an intermediate heat treatment, and a dissimilar metal weld between the nozzle buttering and safe-end. The process can be both time consuming and costly, and often provides difficulties for inspection of welds in the field. Through the use of powder metallurgy and hot isostatic pressing (PM-HIP), a series of transition joint configurations have been evaluated that could reduce the complexity of nozzle-to-safe end fabrication by eliminating fusion welding from the process. Test coupons of SA508 low alloy steel have been joined via PM-HIP to either 316L SS or 347NG SS using various powder metal interlayer materials (Alloy 82, Nb-modified Alloy 600 (600M), Alloy 690, and 316L SS). The microstructural evolution and mechanical performance of the joints have been evaluated following a post-HIP solution anneal, quench and temper heat treatment. Particular attention was given to evaluating bond-line regions via Charpy V-notch impact testing, tensile testing, microhardness, optical microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. Results demonstrate that multiple transition layer configurations are capable of meeting the acceptable tensile and impact energy specifications of the two parent base material substrates. Interface impact toughness and ductility were dependent upon secondary phase precipitation within the diffusion region of the joints and presence of non-metallic inclusions. This assessment demonstrates that acceptable joint performance is achievable through proper material selection and should be considered for DMW applications in the future.

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